Application

This enzyme is useful for enzymatic determination of total cholesterol when coupled with cholesterol oxidase in clinical analysis.

Biochem/physiol Actions

Cholesterol esterase (CE) is a reversible enzyme that can hydrolyze or synthesize fatty acid esters of cholesterol and other sterols. Hydrolysis of water insoluble long chain fatty acid esters requires bile salt activation. Hydrolysis of water soluble esters of short chain fatty acids and lysophospholipids does not require activation by bile salts. It also hydrolyzes tri-, di-, and mono-acylglycerols, phospholipids, lysophospholipids, and ceramide. The enzyme may have multiple functions in lipid and lipoprotein metabolism, and atherosclerosis.

Physical properties

Stability: Stable at –20°C for at least one yearIsoelectric point: 5.9 ± 0.1Michaelis constants: 5.4 x 10‾⁵M (Linoleate), 6.6 x 10‾⁵M (Oleate) 3.7 x 10‾⁵M (Linolenate), 1.5 x 10‾⁴M (Palmitate) 1.2 x 10‾⁴M (Myristate), 2.3 x 10‾⁵M (Stearate)Inhibitors: Hg^++, Ag⁺, ionic detergentsOptimum pH: 7.0 − 9.0Optimum temp: 40°CpH Stability: pH 5.0 − 9.0 (25°C, 24hr)Thermal stability: Below 55°C (pH 7.5, 10min)

Unit Definition

One unit will hydrolyze 1.0 µmole of cholesteryl oleate to cholesterol and oleic acid per min at pH 7.0 at 37 °C in the presence of taurocholate.